The present invention relates to core components for use in electrical machines and, more particularly, a stator assembly for use in an electrical machine, most typically an electric motor.
Electrical machines such as motors and generators have a stationary element, usually termed a stator, and movable or rotating elements, typically termed the rotor. The interaction between the stator and the rotor is caused by the interaction of a magnetic field generated by either the stator or the rotor. Such magnetic field is usually generated or induced by electric currents in a winding placed on either the stator or the rotor. Such winding usually comprises a plurality of coils wound about a winding support. The winding support is usually comprised of a soft magnetic material which traditionally is made of laminations of selected steel materials. The laminations are insulated from each other in order to reduce eddy currents.
One concern in the design of such electrical machines is the need or desire to reduce the free space by improving the fill factor of the windings. It is desirable that the windings fill as much of the open space as practical to improve the inter action between the electromagnetic field between the stator and the rotor. This produces a more efficient motor or generator. Such terminology is deemed as the power density of the motor.
It has become known also to replace the laminated steel materials of the stator or rotor cores with ferro-magnetic powder particles that are compacted in a powder metallurgy operation to form the winding support. The ferro-magnetic powder particles themselves are electrically insulated from each other so that the resulting compacted product exhibits a low eddy current loss in a manner similar to the use of stacks of laminated steel materials. Such use of compacted metal powders comprised of ferro-magnetic powder particles for cores in electrical machines is disclosed in U.S. Pat. Nos. 6,956,307, 6,300,702 and 6,441,530.
Accordingly, it is an object of the present invention to provide an improved stator assembly for use in an electrical machine wherein the fill factor of the windings is reduced and accordingly, the power density of the motor itself is improved.
It is another object of the present invention to provide an improved stator assembly for use in electrical machines wherein the stator assembly utilizes components comprised of compacted ferrous-magnetic powder.